Beam dependent digital pre-distortion

ABSTRACT

Methods, systems, and devices for wireless communications are described. For example, a transmitting wireless device, such as a user equipment or a base station, may apply a first set of digital pre-distortion (DPD) coefficients to a plurality of antenna elements to form a first transmit beam. The wireless device may determine to switch from using the first transmit beam to using a second transmit beam that is different from the first transmit beam and may apply a second set of DPD coefficients to the plurality of antenna elements to form the second transmit beam, where the second set of DPD coefficients is different from the first set of DPD coefficients. The wireless device may transmit signaling using the second transmit beam based at least in part on applying the second set of DPD coefficients.

CROSS REFERENCE

The present Application for Patent is a continuation of U.S. patentapplication Ser. No. 17/316,238 by GUTMAN et al., entitled “BEAMDEPENDENT DIGITAL PRE-DISTORTION,” filed May 10, 2021, assigned to theassignee hereof, and expressly incorporated by reference herein.

FIELD OF TECHNOLOGY

The following relates to wireless communications, including beamdependent digital pre-distortion (DPD).

BACKGROUND

Wireless communications systems are widely deployed to provide varioustypes of communication content such as voice, video, packet data,messaging, broadcast, and so on. These systems may be capable ofsupporting communication with multiple users by sharing the availablesystem resources (e.g., time, frequency, and power). Examples of suchmultiple-access systems include fourth generation (4G) systems such asLong Term Evolution (LTE) systems, LTE-Advanced (LTE-A) systems, orLTE-A Pro systems, and fifth generation (5G) systems which may bereferred to as New Radio (NR) systems. These systems may employtechnologies such as code division multiple access (CDMA), time divisionmultiple access (TDMA), frequency division multiple access (FDMA),orthogonal FDMA (OFDMA), or discrete Fourier transform spread orthogonalfrequency division multiplexing (DFT-S-OFDM). A wireless multiple-accesscommunications system may include one or more base stations or one ormore network access nodes, each simultaneously supporting communicationfor multiple communication devices, which may be otherwise known as userequipment (UE).

A transmitting device, such as a base station or a UE, may be equippedwith multiple antenna elements each with an associated power amplifier(PA) for transmitting beamformed communications. The antenna elementsand PAs of the transmitting device may be grouped into one or moreantenna modules which may also be referred to as radio frequency (RF)modules. The transmitting device may experience non-linearitiesassociated with operations of the power amplifiers. Thesenon-linearities may compound in transmitting devices that have multipleantenna elements and thus multiple power amplifiers. For example, thenon-linearity caused by each PA may be different.

SUMMARY

The described techniques relate to improved methods, systems, devices,and apparatuses that support beam dependent digital pre-distortion(DPD). Generally, the described techniques provide for the applicationand calibration of beam dependent digital pre-distortion coefficients.

In some wireless communications systems, a DPD engine may power a radiofrequency module including a number of antenna element/power amplifierpairs. In such examples, a single set of DPD coefficients may beeffective if the elements experience the same or similar non-linearcharacteristics. In some examples, however, each antenna element mayexperience different non-linearity characteristics due to differentphysical layouts and beamforming, which may generate different loadingper antenna element.

For example, each DPD engine may apply DPD coefficients to a numberpower amplifier (PA) elements each associated with an antenna element,where the antenna element/PA pairs are distributed across a number ofantenna modules. The non-linearity characteristics of each of the poweramplifier elements may be different and may be affected by a differentantenna loading per beam configuration. This may cause DPD coefficientperformance to be different per beam. In other words, a generalized DPDtraining procedure may determine coefficients that work more effectivelyfor some antenna modules than others.

In some examples, it may be more efficient to perform a DPD trainingprocedure on a per-transmit beam basis. For example, each time atransmit beam is changed, the DPD coefficients may be selected for thenew transmit beam. In some examples, upon an initial boot-up procedure,a device may perform a DPD training procedure and may optionally alsoperform DPD training procedures over time while in operation. Based onthe DPD training procedure (which is performed on a per-beam basis),each time the transmit beam is changed, the device may apply differentDPD coefficients to account for the non-linearity of the arrayconfiguration associated with the new beam.

A method for wireless communication at a wireless device is described.The method may include applying a first set of digital pre-distortioncoefficients to a set of multiple antenna elements to form a firsttransmit beam, determining to switch from using the first transmit beamto using a second transmit beam that is different from the firsttransmit beam, applying a second set of digital pre-distortioncoefficients to the set of multiple antenna elements to form the secondtransmit beam, where the second set of digital pre-distortioncoefficients is different from the first set of digital pre-distortioncoefficients, and transmitting signaling using the second transmit beambased on applying the second set of digital pre-distortion coefficients.

An apparatus for wireless communication at a wireless device isdescribed. The apparatus may include a processor, memory coupled withthe processor, and instructions stored in the memory. The instructionsmay be executable by the processor to cause the apparatus to apply afirst set of digital pre-distortion coefficients to a set of multipleantenna elements to form a first transmit beam, determine to switch fromusing the first transmit beam to using a second transmit beam that isdifferent from the first transmit beam, apply a second set of digitalpre-distortion coefficients to the set of multiple antenna elements toform the second transmit beam, where the second set of digitalpre-distortion coefficients is different from the first set of digitalpre-distortion coefficients, and transmit signaling using the secondtransmit beam based on applying the second set of digital pre-distortioncoefficients.

Another apparatus for wireless communication at a wireless device isdescribed. The apparatus may include means for applying a first set ofdigital pre-distortion coefficients to a set of multiple antennaelements to form a first transmit beam, means for determining to switchfrom using the first transmit beam to using a second transmit beam thatis different from the first transmit beam, means for applying a secondset of digital pre-distortion coefficients to the set of multipleantenna elements to form the second transmit beam, where the second setof digital pre-distortion coefficients is different from the first setof digital pre-distortion coefficients, and means for transmittingsignaling using the second transmit beam based on applying the secondset of digital pre-distortion coefficients.

A non-transitory computer-readable medium storing code for wirelesscommunication at a wireless device is described. The code may includeinstructions executable by a processor to apply a first set of digitalpre-distortion coefficients to a set of multiple antenna elements toform a first transmit beam, determine to switch from using the firsttransmit beam to using a second transmit beam that is different from thefirst transmit beam, apply a second set of digital pre-distortioncoefficients to the set of multiple antenna elements to form the secondtransmit beam, where the second set of digital pre-distortioncoefficients is different from the first set of digital pre-distortioncoefficients, and transmit signaling using the second transmit beambased on applying the second set of digital pre-distortion coefficients.

Some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for selecting, from a setof multiple digital pre-distortion coefficient sets, the second set ofdigital pre-distortion coefficients corresponding to the second transmitbeam.

Some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for determining the set ofmultiple digital pre-distortion coefficient sets based on a calibrationprocess that identifies non-linearity characteristics of the set ofmultiple antenna elements for a set of multiple transmit beams includingthe first transmit beam and the second transmit beam.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, the calibration process mayinclude operations, features, means, or instructions for performing adigital pre-distortion coefficient calibration for each of the set ofmultiple transmit beams based on a dynamic calibration schedule thatoccurs while the wireless device may be operating.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, the calibration process mayinclude operations, features, means, or instructions for performing adigital pre-distortion coefficient calibration for each of the set ofmultiple transmit beams based on powering on the wireless device.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, the set of multiple antennaelements may be grouped into a set of multiple radio frequency modulesand each antenna element of the set of multiple antenna elements may beassociated with a power amplifier.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, the first transmit beam maybe associated with a first direction and the second transmit beam may beassociated with a second direction that may be different from the firstdirection.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, the first set of digitalpre-distortion coefficients and the second set of digital pre-distortioncoefficients may be applied by a single digital pre-distortion enginethat may be common to the set of multiple radio frequency modules.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, the wireless device may be abase station.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, the wireless device may be auser equipment.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an example of a wireless communications system thatsupports beam dependent digital pre-distortion (DPD) in accordance withaspects of the present disclosure.

FIG. 2 illustrates an example of a wireless communications system thatsupports beam dependent DPD in accordance with aspects of the presentdisclosure.

FIGS. 3A and 3B each illustrate an example of a device that support beamdependent DPD in accordance with aspects of the present disclosure.

FIG. 4 illustrates an example of a process flow that supports beamdependent DPD in accordance with aspects of the present disclosure.

FIGS. 5 and 6 show block diagrams of devices that support beam dependentDPD in accordance with aspects of the present disclosure.

FIG. 7 shows a block diagram of a communications manager that supportsbeam dependent DPD in accordance with aspects of the present disclosure.

FIG. 8 shows a diagram of a system including a UE that supports beamdependent DPD in accordance with aspects of the present disclosure.

FIG. 9 shows a diagram of a system including a base station thatsupports beam dependent DPD in accordance with aspects of the presentdisclosure.

FIGS. 10 through 13 show flowcharts illustrating methods that supportbeam dependent DPD in accordance with aspects of the present disclosure.

DETAILED DESCRIPTION

Some wireless communications systems may include communication devices,such as a user equipment (UE) and a base station (e.g., an eNodeB (eNB),a next-generation NodeB or a giga-NodeB, either of which may be referredto as a gNB, or some other base station), that may support beamformingtechniques. A transmitting device, such as a base station or a UE, mayinclude an antenna array with a number of antenna elements that thetransmitting device may use to support beamforming of communicationswith a receiving device. Beamforming may be achieved by combiningsignals communicated via antenna elements of an antenna array such thatsome signals propagating at particular orientations with respect to anantenna array experience constructive interference while othersexperience destructive interference. The adjustment of signalscommunicated via the antenna elements may include a transmitting deviceor a receiving device applying amplitude offsets, phase offsets, or bothto signals carried via the antenna elements associated with the device.Each antenna element may be associated with non-linear components, e.g.,power amplifiers (PAs), such that the radiated power from each antennaelement may be adjusted. As such, the utilization efficiency of radiatedpower may affect wireless communications system design. For example, thetransmitting device may contain non-linear components such as high-powerPAs with limited linear dynamic range. That is, the transmitting devicemay transmit beamformed signaling using a number of antenna elements butthe signaling may be distorted due to a high peak to average power ratio(PAPR) at higher power levels due to the non-linear characteristics ofthe power amplifier associated with each antenna element.

There may be a number of types of distortion including in-banddistortion and out-band distortion. For example, in-band distortion maybe caused by an uncorrelated component of the non-linear output. Thatis, the signaling waveform transmitted by the transmitting device may bedistorted as it is transmitted—however—the distortions may remain withina frequency band in which the transmitting device is configured totransmit. In-band distortion may affect link performance and may affectmutual information or/and error vector magnitude.

Out-band distortion may also be caused by an uncorrelated component ofthe non-linear output. That is, the signaling waveform transmitted bythe transmitting device may be distorted as it is transmitted, however,out-band distortions may interfere with frequency bands adjacent to thefrequency band in which the transmitting device is configured totransmit. This may also be referred to as out of band (00B) adjacentchannel interference (ACI). The ACI may indicate how much an adjacentchannel is polluted (e.g., interfered with) by the transmittedsignaling.

To avoid distortion, power back-off (BO) may be introduced, however thehigher power BO may be associated with less power efficiency resultingin less power being transmitted to the receiving device. Additionally oralternatively, digital pre-distortion (DPD) may be implemented in thetransmitter's digital front end. Using the DPD, the degree of distortionmay be mitigated and may be limited to a target distortion level, whilethe power BO may be minimized. This may improve PA efficiency.

DPD may increase linearity or compensate for non-linearity in PAs. Forexample, a DPD engine may calculate and apply a set of DPD coefficientsto the antenna array of the transmitter which may mitigate distortioncaused by PAs. In some wireless communications systems, (e.g., such ammW communications systems) DPD may be supported by a single DPD enginewhich may apply DPD coefficients to an array of PA elements. In somecases, the PA elements may experience similar non-linearitycharacteristics which may produce a similar effect to wirelesscommunications systems in which a DPD engine supports a single PA.However, in practicality, each PA element may experience differentnon-linearity characteristics due to different physical layouts andbeamforming, which generates different loading per antenna/PA elementpair, especially in examples in which tapering may be applied.

In some examples, a DPD engine may support a small number of PA elementslocated on a single RF or antenna module. In this example the PAnon-linearity coefficients may be similar. However, in some otherexamples, a DPD engine may support a large number of PA elements (e.g.,128 elements or more) distributed across multiple modules. In suchexamples, the non-linearity characteristics may differ due to inherentinconsistencies between each of the PAs and due to different loadingconfigurations of the antenna elements for each configured beam. Thedifferent loading configurations may affect the non-linearityperformance of each PA element as non-linearity differs as a function ofpower output. The non-linearity characteristics of each PA may aggregatebased on the large number of PA elements in each beam configuration andthe DPD performance may vary. In other words, the number of antennaelements being located on different antenna modules may cause differentDPD performance (due to different loading configurations) per beam.

To compensate for the non-linearities caused by beamformedcommunications, the transmitting device may perform a DPD coefficientcalibration for each transmit beam. In some examples, the transmittingdevice may perform a DPD coefficient calibration in a factory settingupon initialization (e.g., upon a first powering up of the transmittingdevice). In some examples, the transmitting device may perform a DPDcoefficient calibration while deployed (e.g., while in operation) basedon a schedule. The transmitting device may determine a DPD coefficientset for each configured beam based on performing the DPD coefficientcalibration. For example, the DPD coefficient set may mitigate anon-linearity caused by each PA in the beam configuration.

The DPD engine of the transmitting device may apply a set of DPDcoefficients to the antenna elements when the transmitting device uses atransmit beam. The set of DPD coefficients may be specific to thetransmit beam. Based on more or more factors, the transmitting devicemay determine to switch from using the first transmit beam forcommunications with a receiving device, such as a base station or a UE,to using a second transmit beam that is different from the firsttransmit beam and may select a second set of DPD coefficients thatcorrespond to the second transmit beam configuration. The DPD engine ofthe transmitting device may apply the second set of DPD coefficients tothe plurality of antenna elements based on the transmitting device usingthe second transmit beam. The second set of DPD coefficients may bedifferent from the first set of DPD coefficients. The transmittingdevice may transmit signaling using the second transmit beam based onthe DPD engine applying the second set of DPD coefficients. In such away, the transmitting device may be able to calibrate and applybeam-specific DPD thereby increasing coverage and conserving energy.

Aspects of the disclosure are initially described in the context ofwireless communications systems. Device and process flows are thendescribed. Aspects of the disclosure are further illustrated by anddescribed with reference to apparatus diagrams, system diagrams, andflowcharts that relate to beam dependent DPD.

FIG. 1 illustrates an example of a wireless communications system 100that supports beam dependent DPD in accordance with aspects of thepresent disclosure. The wireless communications system 100 may includeone or more base stations 105, one or more UEs 115, and a core network130. In some examples, the wireless communications system 100 may be aLong Term Evolution (LTE) network, an LTE-Advanced (LTE-A) network, anLTE-A Pro network, or a New Radio (NR) network. In some examples, thewireless communications system 100 may support enhanced broadbandcommunications, ultra-reliable (e.g., mission critical) communications,low latency communications, communications with low-cost andlow-complexity devices, or any combination thereof.

The base stations 105 may be dispersed throughout a geographic area toform the wireless communications system 100 and may be devices indifferent forms or having different capabilities. The base stations 105and the UEs 115 may wirelessly communicate via one or more communicationlinks 125. Each base station 105 may provide a coverage area 110 overwhich the UEs 115 and the base station 105 may establish one or morecommunication links 125. The coverage area 110 may be an example of ageographic area over which a base station 105 and a UE 115 may supportthe communication of signals according to one or more radio accesstechnologies.

The UEs 115 may be dispersed throughout a coverage area 110 of thewireless communications system 100, and each UE 115 may be stationary,or mobile, or both at different times. The UEs 115 may be devices indifferent forms or having different capabilities. Some example UEs 115are illustrated in FIG. 1 . The UEs 115 described herein may be able tocommunicate with various types of devices, such as other UEs 115, thebase stations 105, or network equipment (e.g., core network nodes, relaydevices, integrated access and backhaul (IAB) nodes, or other networkequipment), as shown in FIG. 1 .

The base stations 105 may communicate with the core network 130, or withone another, or both. For example, the base stations 105 may interfacewith the core network 130 through one or more backhaul links 120 (e.g.,via an S1, N2, N3, or other interface). The base stations 105 maycommunicate with one another over the backhaul links 120 (e.g., via anX2, Xn, or other interface) either directly (e.g., directly between basestations 105), or indirectly (e.g., via core network 130), or both. Insome examples, the backhaul links 120 may be or include one or morewireless links.

One or more of the base stations 105 described herein may include or maybe referred to by a person having ordinary skill in the art as a basetransceiver station, a radio base station, an access point, a radiotransceiver, a NodeB, an eNodeB (eNB), a next-generation NodeB or agiga-NodeB (either of which may be referred to as a gNB), a Home NodeB,a Home eNodeB, or other suitable terminology.

A UE 115 may include or may be referred to as a mobile device, awireless device, a remote device, a handheld device, or a subscriberdevice, or some other suitable terminology, where the “device” may alsobe referred to as a unit, a station, a terminal, or a client, amongother examples. A UE 115 may also include or may be referred to as apersonal electronic device such as a cellular phone, a personal digitalassistant (PDA), a tablet computer, a laptop computer, or a personalcomputer. In some examples, a UE 115 may include or be referred to as awireless local loop (WLL) station, an Internet of Things (IoT) device,an Internet of Everything (IoE) device, or a machine type communications(MTC) device, among other examples, which may be implemented in variousobjects such as appliances, or vehicles, meters, among other examples.

The UEs 115 described herein may be able to communicate with varioustypes of devices, such as other UEs 115 that may sometimes act as relaysas well as the base stations 105 and the network equipment includingmacro eNBs or gNBs, small cell eNBs or gNBs, or relay base stations,among other examples, as shown in FIG. 1 .

The UEs 115 and the base stations 105 may wirelessly communicate withone another via one or more communication links 125 over one or morecarriers. The term “carrier” may refer to a set of radio frequencyspectrum resources having a defined physical layer structure forsupporting the communication links 125. For example, a carrier used fora communication link 125 may include a portion of a radio frequencyspectrum band (e.g., a bandwidth part (BWP)) that is operated accordingto one or more physical layer channels for a given radio accesstechnology (e.g., LTE, LTE-A, LTE-A Pro, NR). Each physical layerchannel may carry acquisition signaling (e.g., synchronization signals,system information), control signaling that coordinates operation forthe carrier, user data, or other signaling. The wireless communicationssystem 100 may support communication with a UE 115 using carrieraggregation or multi-carrier operation. A UE 115 may be configured withmultiple downlink component carriers and one or more uplink componentcarriers according to a carrier aggregation configuration. Carrieraggregation may be used with both frequency division duplexing (FDD) andtime division duplexing (TDD) component carriers.

Signal waveforms transmitted over a carrier may be made up of multiplesubcarriers (e.g., using multi-carrier modulation (MCM) techniques suchas orthogonal frequency division multiplexing (OFDM) or discrete Fouriertransform spread OFDM (DFT-S-OFDM)). In a system employing MCMtechniques, a resource element may consist of one symbol period (e.g., aduration of one modulation symbol) and one subcarrier, where the symbolperiod and subcarrier spacing are inversely related. The number of bitscarried by each resource element may depend on the modulation scheme(e.g., the order of the modulation scheme, the coding rate of themodulation scheme, or both). Thus, the more resource elements that a UE115 receives and the higher the order of the modulation scheme, thehigher the data rate may be for the UE 115. A wireless communicationsresource may refer to a combination of a radio frequency spectrumresource, a time resource, and a spatial resource (e.g., spatial layersor beams), and the use of multiple spatial layers may further increasethe data rate or data integrity for communications with a UE 115.

The time intervals for the base stations 105 or the UEs 115 may beexpressed in multiples of a basic time unit which may, for example,refer to a sampling period of T_(s)=1/(Δf_(max)·N_(f)) seconds, whereΔf_(max) may represent the maximum supported subcarrier spacing, andN_(f) may represent the maximum supported discrete Fourier transform(DFT) size. Time intervals of a communications resource may be organizedaccording to radio frames each having a specified duration (e.g., 10milliseconds (ms)). Each radio frame may be identified by a system framenumber (SFN) (e.g., ranging from 0 to 1023).

Each frame may include multiple consecutively numbered subframes orslots, and each subframe or slot may have the same duration. In someexamples, a frame may be divided (e.g., in the time domain) intosubframes, and each subframe may be further divided into a number ofslots. Alternatively, each frame may include a variable number of slots,and the number of slots may depend on subcarrier spacing. Each slot mayinclude a number of symbol periods (e.g., depending on the length of thecyclic prefix prepended to each symbol period). In some wirelesscommunications systems 100, a slot may further be divided into multiplemini-slots containing one or more symbols. Excluding the cyclic prefix,each symbol period may contain one or more (e.g., N_(f)) samplingperiods. The duration of a symbol period may depend on the subcarrierspacing or frequency band of operation.

A subframe, a slot, a mini-slot, or a symbol may be the smallestscheduling unit (e.g., in the time domain) of the wirelesscommunications system 100 and may be referred to as a transmission timeinterval (TTI). In some examples, the TTI duration (e.g., the number ofsymbol periods in a TTI) may be variable. Additionally or alternatively,the smallest scheduling unit of the wireless communications system 100may be dynamically selected (e.g., in bursts of shortened TTIs (sTTIs)).

Physical channels may be multiplexed on a carrier according to varioustechniques. A physical control channel and a physical data channel maybe multiplexed on a downlink carrier, for example, using one or more oftime division multiplexing (TDM) techniques, frequency divisionmultiplexing (FDM) techniques, or hybrid TDM-FDM techniques. A controlregion (e.g., a control resource set (CORESET)) for a physical controlchannel may be defined by a number of symbol periods and may extendacross the system bandwidth or a subset of the system bandwidth of thecarrier. One or more control regions (e.g., CORESETs) may be configuredfor a set of the UEs 115. For example, one or more of the UEs 115 maymonitor or search control regions for control information according toone or more search space sets, and each search space set may include oneor multiple control channel candidates in one or more aggregation levelsarranged in a cascaded manner. An aggregation level for a controlchannel candidate may refer to a number of control channel resources(e.g., control channel elements (CCEs)) associated with encodedinformation for a control information format having a given payloadsize. Search space sets may include common search space sets configuredfor sending control information to multiple UEs 115 and UE-specificsearch space sets for sending control information to a specific UE 115.

In some examples, a base station 105 may be movable and thereforeprovide communication coverage for a moving geographic coverage area110. In some examples, different geographic coverage areas 110associated with different technologies may overlap, but the differentgeographic coverage areas 110 may be supported by the same base station105. In other examples, the overlapping geographic coverage areas 110associated with different technologies may be supported by differentbase stations 105. The wireless communications system 100 may include,for example, a heterogeneous network in which different types of thebase stations 105 provide coverage for various geographic coverage areas110 using the same or different radio access technologies.

The wireless communications system 100 may be configured to supportultra-reliable communications or low-latency communications, or variouscombinations thereof. For example, the wireless communications system100 may be configured to support ultra-reliable low-latencycommunications (URLLC) or mission critical communications. The UEs 115may be designed to support ultra-reliable, low-latency, or criticalfunctions (e.g., mission critical functions). Ultra-reliablecommunications may include private communication or group communicationand may be supported by one or more mission critical services such asmission critical push-to-talk (MCPTT), mission critical video (MCVideo),or mission critical data (MCData). Support for mission criticalfunctions may include prioritization of services, and mission criticalservices may be used for public safety or general commercialapplications. The terms ultra-reliable, low-latency, mission critical,and ultra-reliable low-latency may be used interchangeably herein.

In some examples, a UE 115 may also be able to communicate directly withother UEs 115 over a device-to-device (D2D) communication link 135(e.g., using a peer-to-peer (P2P) or D2D protocol). One or more UEs 115utilizing D2D communications may be within the geographic coverage area110 of a base station 105. Other UEs 115 in such a group may be outsidethe geographic coverage area 110 of a base station 105 or be otherwiseunable to receive transmissions from a base station 105. In someexamples, groups of the UEs 115 communicating via D2D communications mayutilize a one-to-many (1:M) system in which each UE 115 transmits toevery other UE 115 in the group. In some examples, a base station 105facilitates the scheduling of resources for D2D communications. In othercases, D2D communications are carried out between the UEs 115 withoutthe involvement of a base station 105.

The core network 130 may provide user authentication, accessauthorization, tracking, Internet Protocol (IP) connectivity, and otheraccess, routing, or mobility functions. The core network 130 may be anevolved packet core (EPC) or 5G core (5GC), which may include at leastone control plane entity that manages access and mobility (e.g., amobility management entity (MME), an access and mobility managementfunction (AMF)) and at least one user plane entity that routes packetsor interconnects to external networks (e.g., a serving gateway (S-GW), aPacket Data Network (PDN) gateway (P-GW), or a user plane function(UPF)). The control plane entity may manage non-access stratum (NAS)functions such as mobility, authentication, and bearer management forthe UEs 115 served by the base stations 105 associated with the corenetwork 130. User IP packets may be transferred through the user planeentity, which may provide IP address allocation as well as otherfunctions. The user plane entity may be connected to IP services 150 forone or more network operators. The IP services 150 may include access tothe Internet, Intranet(s), an IP Multimedia Subsystem (IMS), or aPacket-Switched Streaming Service.

Some of the network devices, such as a base station 105, may includesubcomponents such as an access network entity 140, which may be anexample of an access node controller (ANC). Each access network entity140 may communicate with the UEs 115 through one or more other accessnetwork transmission entities 145, which may be referred to as radioheads, smart radio heads, or transmission/reception points (TRPs). Eachaccess network transmission entity 145 may include one or more antennapanels. In some configurations, various functions of each access networkentity 140 or base station 105 may be distributed across various networkdevices (e.g., radio heads and ANCs) or consolidated into a singlenetwork device (e.g., a base station 105).

The wireless communications system 100 may operate using one or morefrequency bands, typically in the range of 300 megahertz (MHz) to 300gigahertz (GHz). Generally, the region from 300 MHz to 3 GHz is known asthe ultra-high frequency (UHF) region or decimeter band because thewavelengths range from approximately one decimeter to one meter inlength. The UHF waves may be blocked or redirected by buildings andenvironmental features, but the waves may penetrate structuressufficiently for a macro cell to provide service to the UEs 115 locatedindoors. The transmission of UHF waves may be associated with smallerantennas and shorter ranges (e.g., less than 100 kilometers) compared totransmission using the smaller frequencies and longer waves of the highfrequency (HF) or very high frequency (VHF) portion of the spectrumbelow 300 MHz.

The wireless communications system 100 may utilize both licensed andunlicensed radio frequency spectrum bands. For example, the wirelesscommunications system 100 may employ License Assisted Access (LAA),LTE-Unlicensed (LTE-U) radio access technology, or NR technology in anunlicensed band such as the 5 GHz industrial, scientific, and medical(ISM) band. When operating in unlicensed radio frequency spectrum bands,devices such as the base stations 105 and the UEs 115 may employ carriersensing for collision detection and avoidance. In some examples,operations in unlicensed bands may be based on a carrier aggregationconfiguration in conjunction with component carriers operating in alicensed band (e.g., LAA). Operations in unlicensed spectrum may includedownlink transmissions, uplink transmissions, P2P transmissions, or D2Dtransmissions, among other examples.

A base station 105 or a UE 115 may be equipped with multiple antennas,which may be used to employ techniques such as transmit diversity,receive diversity, multiple-input multiple-output (MIMO) communications,or beamforming. The antennas of a base station 105 or a UE 115 may belocated within one or more antenna arrays or antenna panels, which maysupport MIMO operations or transmit or receive beamforming. For example,one or more base station antennas or antenna arrays may be co-located atan antenna assembly, such as an antenna tower. In some examples,antennas or antenna arrays associated with a base station 105 may belocated in diverse geographic locations. A base station 105 may have anantenna array with a number of rows and columns of antenna ports thatthe base station 105 may use to support beamforming of communicationswith a UE 115. Likewise, a UE 115 may have one or more antenna arraysthat may support various MIMO or beamforming operations. Additionally oralternatively, an antenna panel may support radio frequency beamformingfor a signal transmitted via an antenna port.

Beamforming, which may also be referred to as spatial filtering,directional transmission, or directional reception, is a signalprocessing technique that may be used at a transmitting device or areceiving device (e.g., a base station 105, a UE 115) to shape or steeran antenna beam (e.g., a transmit beam, a receive beam) along a spatialpath between the transmitting device and the receiving device.Beamforming may be achieved by combining the signals communicated viaantenna elements of an antenna array such that some signals propagatingat particular orientations with respect to an antenna array experienceconstructive interference while others experience destructiveinterference. The adjustment of signals communicated via the antennaelements may include a transmitting device or a receiving deviceapplying amplitude offsets, phase offsets, or both to signals carriedvia the antenna elements associated with the device. The adjustmentsassociated with each of the antenna elements may be defined by abeamforming weight set associated with a particular orientation (e.g.,with respect to the antenna array of the transmitting device orreceiving device, or with respect to some other orientation).

A base station 105 or a UE 115 may use beam sweeping techniques as partof beam forming operations. For example, a base station 105 may usemultiple antennas or antenna arrays (e.g., antenna panels) to conductbeamforming operations for directional communications with a UE 115.Some signals (e.g., synchronization signals, reference signals, beamselection signals, or other control signals) may be transmitted by abase station 105 multiple times in different directions. For example,the base station 105 may transmit a signal according to differentbeamforming weight sets associated with different directions oftransmission. Transmissions in different beam directions may be used toidentify (e.g., by a transmitting device, such as a base station 105, orby a receiving device, such as a UE 115) a beam direction for latertransmission or reception by the base station 105.

Some signals, such as data signals associated with a particularreceiving device, may be transmitted by a base station 105 in a singlebeam direction (e.g., a direction associated with the receiving device,such as a UE 115). In some examples, the beam direction associated withtransmissions along a single beam direction may be determined based on asignal that was transmitted in one or more beam directions. For example,a UE 115 may receive one or more of the signals transmitted by the basestation 105 in different directions and may report to the base station105 an indication of the signal that the UE 115 received with a highestsignal quality or an otherwise acceptable signal quality.

In some examples, transmissions by a device (e.g., by a base station 105or a UE 115) may be performed using multiple beam directions, and thedevice may use a combination of digital precoding or radio frequencybeamforming to generate a combined beam for transmission (e.g., from abase station 105 to a UE 115). The UE 115 may report feedback thatindicates precoding weights for one or more beam directions, and thefeedback may correspond to a configured number of beams across a systembandwidth or one or more sub-bands. The base station 105 may transmit areference signal (e.g., a cell-specific reference signal (CRS), achannel state information reference signal (CSI-RS)), which may beprecoded or unprecoded. The UE 115 may provide feedback for beamselection, which may be a precoding matrix indicator (PMI) orcodebook-based feedback (e.g., a multi-panel type codebook, a linearcombination type codebook, a port selection type codebook). Althoughthese techniques are described with reference to signals transmitted inone or more directions by a base station 105, a UE 115 may employsimilar techniques for transmitting signals multiple times in differentdirections (e.g., for identifying a beam direction for subsequenttransmission or reception by the UE 115) or for transmitting a signal ina single direction (e.g., for transmitting data to a receiving device).

A receiving device (e.g., a UE 115) may try multiple receiveconfigurations (e.g., directional listening) when receiving varioussignals from the base station 105, such as synchronization signals,reference signals, beam selection signals, or other control signals. Forexample, a receiving device may try multiple receive directions byreceiving via different antenna subarrays, by processing receivedsignals according to different antenna subarrays, by receiving accordingto different receive beamforming weight sets (e.g., differentdirectional listening weight sets) applied to signals received atmultiple antenna elements of an antenna array, or by processing receivedsignals according to different receive beamforming weight sets appliedto signals received at multiple antenna elements of an antenna array,any of which may be referred to as “listening” according to differentreceive configurations or receive directions. In some examples, areceiving device may use a single receive configuration to receive alonga single beam direction (e.g., when receiving a data signal). The singlereceive configuration may be aligned in a beam direction determinedbased on listening according to different receive configurationdirections (e.g., a beam direction determined to have a highest signalstrength, highest signal-to-noise ratio (SNR), or otherwise acceptablesignal quality based on listening according to multiple beamdirections).

A transmitting device 180, which may be an example of a base station 105or a UE 115, may be equipped with a PA corresponding to each of itsantenna elements and a single DPD engine 185 common to each of aplurality of RF modules in which the antenna elements and PAs aredistributed. When beamforming, the transmitting device 180 mayexperience non-linearities associated with the operations of each poweramplifier. For example, the transmitting device 180 may be configured totransmit using a plurality of beams (e.g., using a single beam of theplurality of beams at a time) and each beam may be formed based on aload of each antenna element. In such examples, each beam may beassociated with a non-linearity caused by the antenna elementconfiguration and each beam non-linearity may be different. Tocompensate for the non-linearities caused by beamformed communications,the transmitting device 180 may perform a DPD coefficient calibrationfor each of the plurality of transmit beams. In some examples, thetransmitting device 180 may perform a DPD coefficient calibration in afactory setting upon initialization (e.g., upon a first powering up ofthe transmitting device). Additionally or alternatively, thetransmitting device 180 may perform a DPD coefficient calibration whiledeployed (e.g., while in operation) based on a schedule. Based on theDPD coefficient calibration, the transmitting device 180 may determine aDPD coefficient set for each configured beam. For example, the DPDcoefficient set may account for a non-linearity caused by each PA in thebeam configuration.

The DPD engine 185 of the transmitting device 180 may apply a first setof DPD coefficients to the antenna elements when the transmitting device180 forms a first transmit beam. Based on more or more factors, thetransmitting device 180 may determine to switch from using the firsttransmit beam for communications with a receiving device, such as a basestation 105 or a UE 115, to using a second transmit beam that isdifferent from the first transmit beam and may select a set of DPDcoefficients that correspond to the second transmit beam configuration.The DPD engine 185 of the transmitting device 180 may apply a second setof DPD coefficients to the plurality of antenna elements when thetransmitting device forms the second transmit beam. The second set ofDPD coefficients may be different from the first set of DPDcoefficients. The transmitting device 180 may transmit signaling usingthe second transmit beam based on the DPD engine 185 applying the secondset of DPD coefficients.

FIG. 2 illustrates an example of a wireless communications system 200that supports beam dependent DPD in accordance with aspects of thepresent disclosure. In some examples, the wireless communications system200 may implement aspects of wireless communications systems 100.Wireless communications system 200 includes a receiving device 205 whichmay be an example of a UE 115 or base station 105 as described withreference to FIG. 1 . In some examples, the receiving device 205 may bean example of a relay device, IAB nodes, or other network equipment.Wireless communications system 200 also includes a transmitting device210 which may be an example of a transmitting device 180 as describedwith reference to FIG. 1 , which may also be an example of a basestation 105 or a UE 115, among other examples. In some examples, thetransmitting device 210 may be an example of a relay device, integratedaccess and backhaul (IAB) nodes, or other network equipment.

The transmitting device 210 may be configured to transmit using a numberof beamformed transmit beams 220. The transmitting device 210 mayinclude an antenna module 215. In some examples, while not shown, thetransmitting device 210 may include more than one antenna module 215.For example, the transmitting device 210 may include 8 antenna modulesin some implementations. The antenna module 215 may include a number ofPAs 225 and antenna elements 230. While FIG. 2 explicitly depicts anantenna module having eight antenna elements 230 and eight PAs 225, itis to be understood that the example is for illustrative purpose and isnot limiting. A transmitting device 210 may have any number of PA 225and antenna 230 as may an individual antenna module 215.

Each PA 225 may be associated with a non-linearity at certain radiatedpower levels. For example, graph 235 shows an example non-linearitycaused by a PA 225-e, for example. The graph 235 shows a signal in thecontext of an input signal V_(i) and an output signal, V_(o). That is,the signal may be received at the PA 225-e at a voltage, V_(i) and maybe transmitted by the PA 225-e at a voltage, V_(o). If the PA 225-e werean ideal PA, V_(i) would be linearly related to V_(o). For example,curve 250 may be an example of a linear relationship between V_(i) andV_(o). However, in many cases, PAs may cause non-linear effects. Forexample, the PA 225-e may cause a non-linear relationship 260 betweenV_(i) and V_(o) which may be referred to as distortion. Likewise, otherPAs 225 may cause non-linear effects, however such effects may bedifferent from the non-linear effects caused by PA 225-e especially whenconsidering beamforming configurations. For example, each PA element 225may experience different non-linearity characteristics due to differentphysical layouts and beamforming configurations, which generatesdifferent loading configurations per antenna/PA element pair.

To avoid such distortion, DPD may be implemented. For example, a set ofDPD coefficients may be applied to a signal input such that the signalinput, V_(i) at the PA 225 may be linearly related to V_(o). However, asingle set of DPD coefficients may be insufficient to linearize thesignal responses at each PA 225 because different loading configurationsfor different beams 220 may affect the non-linearity performance of eachPA element as non-linearity differs as a function of power output. Thatis, each PA 225 may have a different setting for each beam configuration220. The non-linearity characteristics of each PA 225 may aggregatebased on the number of PA elements. In other words, the number ofantenna elements being located on different antenna modules may causethe set of DPD coefficients to perform differently (due to differentloading configurations) per beam.

To compensate for the non-linearities caused by beamformedcommunications, the transmitting device 210 may perform a DPDcoefficient calibration for each transmit beam 220. In some examples,the transmitting device 210 may perform a DPD coefficient calibration ina factory setting upon initialization (e.g., upon a first powering up ofthe transmitting device 210). In some examples, the transmitting devicemay perform a DPD coefficient calibration while deployed (e.g., while inoperation) based on a schedule. The transmitting device 210 maydetermine a DPD coefficient set for each configured beam 220 based onperforming the DPD coefficient calibration. A DPD coefficientcalibration may include transmitting signaling using a directional beamat a known power or orientation (or other measurable characteristic) andthen measuring the received power or orientation (or other measurablecharacteristic) to assess the distortion caused by the non-linearity.Based on this measured distortion, a set of DPD coefficients may beselected that compensates for the distortion. This procedure may berepeated for each directional beam that is formable by the transmittingdevice. For example, the DPD coefficient set may mitigate anon-linearity caused by each PA 225 in the beam configuration.

The transmitting device 210 may apply a set of DPD coefficients to asignal transmitted to the antenna elements 230 when the transmittingdevice 210 uses a transmit beam 220-a. The set of DPD coefficients maybe specific to the transmit beam 220-a. Based on more or more factors,the transmitting device 210 may determine to switch from using the firsttransmit beam 220-a for communications with the receiving device 205, tousing a second transmit beam 220-b that is different from the firsttransmit beam 220-a and may select a second set of DPD coefficients thatcorrespond to the second transmit beam configuration 220-b. Thetransmitting device 210 may apply the second set of DPD coefficients tothe plurality of antenna elements 230 (e.g., may apply the DPDcoefficients to a signal before transmitting the signal using theantenna elements 230 via the PA 225) based on the transmitting device210 determining to use the second transmit beam 220-b. The second set ofDPD coefficients may be different from the first set of DPDcoefficients. The transmitting device 210 may transmit signaling usingthe second transmit beam 220-b based on the DPD engine applying thesecond set of DPD coefficients. In such a way, the transmitting device210 may be able to calibrate and apply beam-specific DPD therebyincreasing coverage and conserving energy by linearizing the signaloutput by the antenna 230. For example, the DPD may apply a curve 240 tothe non-linear relationship 260 such that the signal output is morelinear.

FIG. 3A illustrates an example of a device 301 that supports beamdependent DPD in accordance with aspects of the present disclosure. Thedevice 301 may be an example of portions of a device architecture whichmay be implemented in, for example, a UE 115, a relay device, IAB nodes,or other network equipment as described with reference to FIG. 1 . Thedevice 301 may include a DPD engine 305-a, an intermediate frequencyamplifier 310-a, and an RF module 315-a. The RF module 315-a may includea number of antenna elements with a corresponding number of PAs and aninternal splitter for splitting signals received from the intermediatefrequency (IF) amplifier 310-a among the antenna elements.

The DPD engine 305-a may transmit a set of DPD coefficients to theintermediate frequency amplifier 310-a. The IF amplifier 310-a mayamplify the signal frequencies and may transmit the signal to theantenna module 315-a. The antenna module 315-a may be configured totransmit the signal based on a beamformed configuration of the antennaelements and may transmit the signal based on the DPD coefficientsreceived from the DPD engine 305-a. In such a way, the device 301 maymitigate non-linearity effects caused by the PAs of the antenna module315-a.

FIG. 3B illustrates an example of a device 302 that supports beamdependent DPD in accordance with aspects of the present disclosure. Thedevice 302 may be an example of portions of a device architecture whichmay be implemented in, for example, a base station 105, a relay device,IAB nodes, or other network equipment, which are described withreference to FIG. 1 . The device 302 may include a DPD engine 305-b, anIF amplifier 310-b, a splitter component 320, and a number of antennamodules 315-b through 315-n. The antenna modules 315 may include anumber of antenna elements with a corresponding number of PAs.

With reference to FIG. 3A, the RF module 315-a may be associated with anRF chip which may affect the non-linearity characteristics of theantenna elements. For example, while each power amplifier and thus eachbeam configuration of the RF module 315-a may have differentnon-linearity characteristics, such differences may be insignificantwhen compared to devices with multiple RF modules (e.g., and thusmultiple RF chips) such as device 302. With reference to FIG. 3B, thenon-linearity condition of the device 302 may be amplified as theantenna elements are distributed across multiple RF chips. Atransmitting device may include a device 302 which may have, forexample, 128 elements (e.g., 128 PAs corresponding to each of 128antennas), which may be distributed across a number of antenna modulesamong a number of RF chips. This may cause an increased non-linearitycharacteristic based on an aggregated distortion from each of the RFchips. Additionally, the aggregated distortion may differ based on eachbeam configuration. For example, the aggregated distortion caused by theantenna module configuration transmitting a first beam may be differentthan when transmitting a second beam. With reference to FIG. 3A, adevice 301 may have a smaller number of antenna elements located on asingle RF chip which may cause a lesser or more predictable distortioneffect, however, the device 301 may still benefit from a per-beam DPDcoefficient calibration even if less significantly than would device302.

FIG. 4 illustrates an example of a process flow 400 that supports beamdependent DPD in accordance with aspects of the present disclosure. Insome examples, the process flow 400 may implement aspects of wirelesscommunications systems 100 and/or 200. Process flow 400 includes areceiving device 405 which may be an example of a UE 115, base station105, a relay device, IAB nodes, or other network equipment as describedwith reference to FIG. 1 . Process flow 400 also includes a transmittingdevice 410 which may be an example of a transmitting device 180 asdescribed with reference to FIG. 1 or a transmitting device 210 asdescribed with reference to FIG. 2 each of which may be an example of abase station 105 or a UE 115, among other examples.

In the following description of the process flow 400, the operationsbetween the receiving device 405 and the transmitting device 410 may betransmitted in a different order than the exemplary order shown, oroperations performed by the transmitting device 410 may be performed indifferent orders, at different times, or by different entities. Certainoperations may also be left out of the process flow 400, or otheroperations may be added to the process flow 400. It is to be understoodthat while the transmitting device 410 is shown performing a number ofthe operations of process flow 400, any wireless device may perform theoperations shown. Process flow 400 may illustrate a procedure for beamdependent digital pre-distortion calibration.

At 415, the transmitting device 410 may perform a DPD coefficientcalibration for each of the plurality of transmit beams. In someexamples, the transmitting device 410 may perform a DPD coefficientcalibration in a factory setting upon initialization (e.g., upon a firstpowering up of the transmitting device). For example, an initial DPDcoefficient calibration may be performed as part of initializing thetransmitting device 410 or as part of manufacturing transmitting device410. In some examples, the transmitting device 180 may perform a DPDcoefficient calibration in an online setting (e.g., when deployed, whilein operation, etc.) based on a schedule. The schedule, for example maybe determined based on a number of factors including an age of thetransmitting device 410, locational conditions of the transmittingdevice 410 (e.g., ambient temperature, day/night temperaturefluctuations, among other examples,), usage of the transmitting device410, etc. In some examples, the schedule may be dynamic and may changethroughout the lifetime of the transmitting device 410. Based on the DPDcoefficient calibration, the transmitting device 410 may determine a DPDcoefficient set for each configured transmit beam. For example, the DPDcoefficient set may account for a non-linearity caused by each RF module(e.g., including a number of antenna element/PA pairs) in each beamconfiguration. The calibration process may include calculating a set ofcoefficients based on the non-linearity characteristics of the RFmodules or the individual PAs in each beam configuration, which on amodule-by-module (e.g., or PA element-by-PA element) basis may bedifferent for each beam configuration.

At 420, the transmitting device may determine to communicate with thereceiving device 405 using a first transmit beam. The transmittingdevice 410 may select, and a DPD engine of the transmitting device 410may apply, a corresponding first set of DPD coefficients to the antennaelements in the first transmit beam configuration. The correspondingfirst set of DPD coefficients may be calculated during the calibrationprocess and may mitigate non-linearities caused by the antenna elementconfiguration associated with the first transmit beam. For example, thecorresponding first set of DPD coefficients may correspond tonon-linearities caused by operational characteristics (e.g., transmitphase, load, power, among other examples) of each antenna element andthe corresponding PA that form the first transmit beam.

At 425, the transmitting device 410 may transmit signaling to thereceiving device 405 using the first transmit beam based on the DPDengine applying the first set of DPD coefficients to the antennaelements.

At 430, and based on a number of factors, the transmitting device 410may determine to switch transmit beams. For example, the transmittingdevice may determine to communicate with the receiving device 405 usinga second transmit beam.

At 435, the transmitting device may select a set of DPD coefficientsthat correspond to the second transmit beam configuration (e.g., asecond set of DPD coefficients). The second set of DPD coefficients maybe selected from the number of beam-dependent DPD coefficient setscalculated during the DPD coefficient calibration process. For example,the corresponding second set of DPD coefficients may correspond tonon-linearities caused by operational characteristics (e.g., transmitphase, load, power, among other examples) of each antenna element andthe corresponding PA that form the second transmit beam.

At 440, the transmitting device 410 may apply the corresponding secondset of DPD coefficients to the antenna elements in the second transmitbeam configuration. The corresponding second set of DPD coefficients,when applied, may mitigate non-linearities caused by the antenna elementconfiguration associated with the second transmit beam. In someexamples, applying a set of DPD coefficients (e.g., applying any of thenumber of beam-dependent DPD coefficient sets) may include applying theDPD coefficients to the operations of the antenna elements, or to theoperations of the PAs, or to the operations of the RF modules which eachinclude a number of antenna element/PA pairs. Applying the set of DPDcoefficients may additionally or alternatively include applying the DPDcoefficients to a processing procedure prior to or after the PAs areimplemented.

At 445, the transmitting device 410 may transmit second signaling to thereceiving device 405 using the second transmit beam based on the DPDengine applying the second set of DPD coefficients to the antennaelements.

FIG. 5 shows a block diagram 500 of a device 505 that supports beamdependent DPD in accordance with aspects of the present disclosure. Thedevice 505 may be an example of aspects of a UE 115 or a base station105 as described herein. The device 505 may include a receiver 510, atransmitter 515, and a communications manager 520. The device 505 mayalso include a processor. Each of these components may be incommunication with one another (e.g., via one or more buses).

The receiver 510 may provide a means for receiving information such aspackets, user data, control information, or any combination thereofassociated with various information channels (e.g., control channels,data channels, information channels related to beam dependent DPD).Information may be passed on to other components of the device 505. Thereceiver 510 may utilize a single antenna or a set of multiple antennas.

The transmitter 515 may provide a means for transmitting signalsgenerated by other components of the device 505. For example, thetransmitter 515 may transmit information such as packets, user data,control information, or any combination thereof associated with variousinformation channels (e.g., control channels, data channels, informationchannels related to beam dependent DPD). In some examples, thetransmitter 515 may be co-located with a receiver 510 in a transceivermodule. The transmitter 515 may utilize a single antenna or a set ofmultiple antennas.

The communications manager 520, the receiver 510, the transmitter 515,or various combinations thereof or various components thereof may beexamples of means for performing various aspects of beam dependent DPDas described herein. For example, the communications manager 520, thereceiver 510, the transmitter 515, or various combinations or componentsthereof may support a method for performing one or more of the functionsdescribed herein.

In some examples, the communications manager 520, the receiver 510, thetransmitter 515, or various combinations or components thereof may beimplemented in hardware (e.g., in communications management circuitry).The hardware may include a processor, a digital signal processor (DSP),an application-specific integrated circuit (ASIC), a field-programmablegate array (FPGA) or other programmable logic device, a discrete gate ortransistor logic, discrete hardware components, or any combinationthereof configured as or otherwise supporting a means for performing thefunctions described in the present disclosure. In some examples, aprocessor and memory coupled with the processor may be configured toperform one or more of the functions described herein (e.g., byexecuting, by the processor, instructions stored in the memory).

Additionally or alternatively, in some examples, the communicationsmanager 520, the receiver 510, the transmitter 515, or variouscombinations or components thereof may be implemented in code (e.g., ascommunications management software or firmware) executed by a processor.If implemented in code executed by a processor, the functions of thecommunications manager 520, the receiver 510, the transmitter 515, orvarious combinations or components thereof may be performed by ageneral-purpose processor, a DSP, a central processing unit (CPU), anASIC, an FPGA, or any combination of these or other programmable logicdevices (e.g., configured as or otherwise supporting a means forperforming the functions described in the present disclosure).

In some examples, the communications manager 520 may be configured toperform various operations (e.g., receiving, monitoring, transmitting)using or otherwise in cooperation with the receiver 510, the transmitter515, or both. For example, the communications manager 520 may receiveinformation from the receiver 510, send information to the transmitter515, or be integrated in combination with the receiver 510, thetransmitter 515, or both to receive information, transmit information,or perform various other operations as described herein.

The communications manager 520 may support wireless communication at awireless device in accordance with examples as disclosed herein. Forexample, the communications manager 520 may be configured as orotherwise support a means for applying a first set of DPD coefficientsto a set of multiple antenna elements to form a first transmit beam. Thecommunications manager 520 may be configured as or otherwise support ameans for determining to switch from using the first transmit beam tousing a second transmit beam that is different from the first transmitbeam. The communications manager 520 may be configured as or otherwisesupport a means for applying a second set of DPD coefficients to the setof multiple antenna elements to form the second transmit beam, where thesecond set of DPD coefficients is different from the first set of DPDcoefficients. The communications manager 520 may be configured as orotherwise support a means for transmitting signaling using the secondtransmit beam based on applying the second set of DPD coefficients.

By including or configuring the communications manager 520 in accordancewith examples as described herein, the device 505 (e.g., a processorcontrolling or otherwise coupled to the receiver 510, the transmitter515, the communications manager 520, or a combination thereof) maysupport techniques for reduced power consumption, and more efficientutilization of communication resources, among other examples.

FIG. 6 shows a block diagram 600 of a device 605 that supports beamdependent DPD in accordance with aspects of the present disclosure. Thedevice 605 may be an example of aspects of a device 505, a UE 115, or abase station 105 as described herein. The device 605 may include areceiver 610, a transmitter 615, and a communications manager 620. Thedevice 605 may also include a processor. Each of these components may bein communication with one another (e.g., via one or more buses).

The receiver 610 may provide a means for receiving information such aspackets, user data, control information, or any combination thereofassociated with various information channels (e.g., control channels,data channels, information channels related to beam dependent DPD).Information may be passed on to other components of the device 605. Thereceiver 610 may utilize a single antenna or a set of multiple antennas.

The transmitter 615 may provide a means for transmitting signalsgenerated by other components of the device 605. For example, thetransmitter 615 may transmit information such as packets, user data,control information, or any combination thereof associated with variousinformation channels (e.g., control channels, data channels, informationchannels related to beam dependent DPD). In some examples, thetransmitter 615 may be co-located with a receiver 610 in a transceivermodule. The transmitter 615 may utilize a single antenna or a set ofmultiple antennas.

The device 605, or various components thereof, may be an example ofmeans for performing various aspects of beam dependent DPD as describedherein. For example, the communications manager 620 may include a DPDcomponent 625, a beam manager 630, a PA transmission component 635, orany combination thereof. The communications manager 620 may be anexample of aspects of a communications manager 520 as described herein.In some examples, the communications manager 620, or various componentsthereof, may be configured to perform various operations (e.g.,receiving, monitoring, transmitting) using or otherwise in cooperationwith the receiver 610, the transmitter 615, or both. For example, thecommunications manager 620 may receive information from the receiver610, send information to the transmitter 615, or be integrated incombination with the receiver 610, the transmitter 615, or both toreceive information, transmit information, or perform various otheroperations as described herein.

The communications manager 620 may support wireless communication at awireless device in accordance with examples as disclosed herein. The DPDcomponent 625 may be configured as or otherwise support a means forapplying a first set of DPD coefficients to a set of multiple antennaelements to form a first transmit beam. The beam manager 630 may beconfigured as or otherwise support a means for determining to switchfrom using the first transmit beam to using a second transmit beam thatis different from the first transmit beam. The DPD component 625 may beconfigured as or otherwise support a means for applying a second set ofDPD coefficients to the set of multiple antenna elements to form thesecond transmit beam, where the second set of DPD coefficients isdifferent from the first set of DPD coefficients. The PA transmissioncomponent 635 may be configured as or otherwise support a means fortransmitting signaling using the second transmit beam based on applyingthe second set of DPD coefficients.

FIG. 7 shows a block diagram 700 of a communications manager 720 thatsupports beam dependent DPD in accordance with aspects of the presentdisclosure. The communications manager 720 may be an example of aspectsof a communications manager 520, a communications manager 620, or both,as described herein. The communications manager 720, or variouscomponents thereof, may be an example of means for performing variousaspects of beam dependent DPD as described herein. For example, thecommunications manager 720 may include a DPD component 725, a beammanager 730, a PA transmission component 735, a DPD manager 740, acalibration component 745, an online calibration component 750, afactory calibration component 755, or any combination thereof. Each ofthese components may communicate, directly or indirectly, with oneanother (e.g., via one or more buses).

The communications manager 720 may support wireless communication at awireless device in accordance with examples as disclosed herein. The DPDcomponent 725 may be configured as or otherwise support a means forapplying a first set of DPD coefficients to a set of multiple antennaelements to form a first transmit beam. The beam manager 730 may beconfigured as or otherwise support a means for determining to switchfrom using the first transmit beam to using a second transmit beam thatis different from the first transmit beam. In some examples, the DPDcomponent 725 may be configured as or otherwise support a means forapplying a second set of DPD coefficients to the set of multiple antennaelements to form the second transmit beam, where the second set of DPDcoefficients is different from the first set of DPD coefficients. The PAtransmission component 735 may be configured as or otherwise support ameans for transmitting signaling using the second transmit beam based onapplying the second set of DPD coefficients.

In some examples, the DPD manager 740 may be configured as or otherwisesupport a means for selecting, from a set of multiple DPD coefficientsets, the second set of DPD coefficients corresponding to the secondtransmit beam.

In some examples, the calibration component 745 may be configured as orotherwise support a means for determining the set of multiple DPDcoefficient sets based on a calibration process that identifiesnon-linearity characteristics of the set of multiple antenna elementsfor a set of multiple transmit beams including the first transmit beamand the second transmit beam.

In some examples, to support calibration process, the online calibrationcomponent 750 may be configured as or otherwise support a means forperforming a DPD coefficient calibration for each of the set of multipletransmit beams based on a dynamic calibration schedule that occurs whilethe wireless device is operating.

In some examples, to support calibration process, the factorycalibration component 755 may be configured as or otherwise support ameans for performing a DPD coefficient calibration for each of the setof multiple transmit beams based on powering on the wireless device.

In some examples, the set of multiple antenna elements are grouped intoa set of multiple radio frequency modules. In some examples, eachantenna element of the set of multiple antenna elements is associatedwith a power amplifier.

In some examples, the first transmit beam is associated with a firstdirection and the second transmit beam is associated with a seconddirection that is different from the first direction.

In some examples, the first set of DPD coefficients and the second setof DPD coefficients are applied by a single DPD engine that is common tothe set of multiple radio frequency modules.

In some examples, the wireless device is a base station. In someexamples, the wireless device is a user equipment.

FIG. 8 shows a diagram of a system 800 including a device 805 thatsupports beam dependent DPD in accordance with aspects of the presentdisclosure. The device 805 may be an example of or include thecomponents of a device 505, a device 605, or a UE 115 or a base station105 as described herein. The device 805 may communicate wirelessly withone or more base stations 105, UEs 115, or any combination thereof. Thedevice 805 may include components for bi-directional voice and datacommunications including components for transmitting and receivingcommunications, such as a communications manager 820, a networkcommunications manager 810, a transceiver 815, an antenna 825, a memory830, code 835, a processor 840, and an inter-station communicationsmanager 845. These components may be in electronic communication orotherwise coupled (e.g., operatively, communicatively, functionally,electronically, electrically) via one or more buses (e.g., a bus 850).

The network communications manager 810 may manage communications with acore network 130 (e.g., via one or more wired backhaul links). Forexample, the network communications manager 810 may manage the transferof data communications for client devices, such as one or more UEs 115.

In some cases, the device 805 may include a single antenna 825. However,in some other cases the device 805 may have more than one antenna 825,which may be capable of concurrently transmitting or receiving multiplewireless transmissions. The transceiver 815 may communicatebi-directionally, via the one or more antennas 825, wired, or wirelesslinks as described herein. For example, the transceiver 815 mayrepresent a wireless transceiver and may communicate bi-directionallywith another wireless transceiver. The transceiver 815 may also includea modem to modulate the packets, to provide the modulated packets to oneor more antennas 825 for transmission, and to demodulate packetsreceived from the one or more antennas 825. The transceiver 815, or thetransceiver 815 and one or more antennas 825, may be an example of atransmitter 515, a transmitter 615, a receiver 510, a receiver 610, orany combination thereof or component thereof, as described herein.

The memory 830 may include random access memory (RAM) and read-onlymemory (ROM). The memory 830 may store computer-readable,computer-executable code 835 including instructions that, when executedby the processor 840, cause the device 805 to perform various functionsdescribed herein. The code 835 may be stored in a non-transitorycomputer-readable medium such as system memory or another type ofmemory. In some cases, the code 835 may not be directly executable bythe processor 840 but may cause a computer (e.g., when compiled andexecuted) to perform functions described herein. In some cases, thememory 830 may contain, among other things, a basic input/output (I/O)system (BIOS) which may control basic hardware or software operationsuch as the interaction with peripheral components or devices.

The processor 840 may include an intelligent hardware device (e.g., ageneral-purpose processor, a DSP, a CPU, a microcontroller, an ASIC, anFPGA, a programmable logic device, a discrete gate or transistor logiccomponent, a discrete hardware component, or any combination thereof).In some cases, the processor 840 may be configured to operate a memoryarray using a memory controller. In some other cases, a memorycontroller may be integrated into the processor 840. The processor 840may be configured to execute computer-readable instructions stored in amemory (e.g., the memory 830) to cause the device 805 to perform variousfunctions (e.g., functions or tasks supporting beam dependent DPD). Forexample, the device 805 or a component of the device 805 may include aprocessor 840 and memory 830 coupled to the processor 840, the processor840 and memory 830 configured to perform various functions describedherein.

The inter-station communications manager 845 may manage communicationswith other base stations 105, and may include a controller or schedulerfor controlling communications with UEs 115 in cooperation with otherbase stations 105. For example, the inter-station communications manager845 may coordinate scheduling for transmissions to UEs 115 for variousinterference mitigation techniques such as beamforming or jointtransmission. In some examples, the inter-station communications manager845 may provide an X2 interface within an LTE/LTE-A wirelesscommunications network technology to provide communication between basestations 105.

The communications manager 820 may support wireless communication at awireless device in accordance with examples as disclosed herein. Forexample, the communications manager 820 may be configured as orotherwise support a means for applying a first set of DPD coefficientsto a set of multiple antenna elements to form a first transmit beam. Thecommunications manager 820 may be configured as or otherwise support ameans for determining to switch from using the first transmit beam tousing a second transmit beam that is different from the first transmitbeam. The communications manager 820 may be configured as or otherwisesupport a means for applying a second set of DPD coefficients to the setof multiple antenna elements to form the second transmit beam, where thesecond set of DPD coefficients is different from the first set of DPDcoefficients. The communications manager 820 may be configured as orotherwise support a means for transmitting signaling using the secondtransmit beam based on applying the second set of DPD coefficients.

By including or configuring the communications manager 820 in accordancewith examples as described herein, the device 805 may support techniquesfor improved communication reliability and coverage, reduced powerconsumption, longer battery life, or reduced interference, among otherexamples.

In some examples, the communications manager 820 may be configured toperform various operations (e.g., receiving, monitoring, transmitting)using or otherwise in cooperation with the transceiver 815, the one ormore antennas 825, or any combination thereof. Although thecommunications manager 820 is illustrated as a separate component, insome examples, one or more functions described with reference to thecommunications manager 820 may be supported by or performed by theprocessor 840, the memory 830, the code 835, or any combination thereof.For example, the code 835 may include instructions executable by theprocessor 840 to cause the device 805 to perform various aspects of beamdependent DPD as described herein, or the processor 840 and the memory830 may be otherwise configured to perform or support such operations.

FIG. 9 shows a diagram of a system 900 including a device 905 thatsupports beam dependent DPD in accordance with aspects of the presentdisclosure. The device 905 may be an example of or include thecomponents of a device 505, a device 605, or a UE 115 or a base station105 as described herein. The device 905 may communicate wirelessly withone or more base stations 105, UEs 115, or any combination thereof. Thedevice 905 may include components for bi-directional voice and datacommunications including components for transmitting and receivingcommunications, such as a communications manager 920, an I/O controller910, a transceiver 915, an antenna 925, a memory 930, code 935, and aprocessor 940. These components may be in electronic communication orotherwise coupled (e.g., operatively, communicatively, functionally,electronically, electrically) via one or more buses (e.g., a bus 945).

The I/O controller 910 may manage input and output signals for thedevice 905. The I/O controller 910 may also manage peripherals notintegrated into the device 905. In some cases, the I/O controller 910may represent a physical connection or port to an external peripheral.In some cases, the I/O controller 910 may utilize an operating systemsuch as iOS®, ANDROID®, MS-DOS®, MS-WINDOWS®, OS/2®, UNIX®, LINUX®, oranother known operating system. Additionally or alternatively, the I/Ocontroller 910 may represent or interact with a modem, a keyboard, amouse, a touchscreen, or a similar device. In some cases, the I/Ocontroller 910 may be implemented as part of a processor, such as theprocessor 940. In some cases, a user may interact with the device 905via the I/O controller 910 or via hardware components controlled by theI/O controller 910.

In some cases, the device 905 may include a single antenna 925. However,in some other cases, the device 905 may have more than one antenna 925,which may be capable of concurrently transmitting or receiving multiplewireless transmissions. The transceiver 915 may communicatebi-directionally, via the one or more antennas 925, wired, or wirelesslinks as described herein. For example, the transceiver 915 mayrepresent a wireless transceiver and may communicate bi-directionallywith another wireless transceiver. The transceiver 915 may also includea modem to modulate the packets, to provide the modulated packets to oneor more antennas 925 for transmission, and to demodulate packetsreceived from the one or more antennas 925. The transceiver 915, or thetransceiver 915 and one or more antennas 925, may be an example of atransmitter 515, a transmitter 615, a receiver 510, a receiver 610, orany combination thereof or component thereof, as described herein.

The memory 930 may include RAM and ROM. The memory 930 may storecomputer-readable, computer-executable code 935 including instructionsthat, when executed by the processor 940, cause the device 905 toperform various functions described herein. The code 935 may be storedin a non-transitory computer-readable medium such as system memory oranother type of memory. In some cases, the code 935 may not be directlyexecutable by the processor 940 but may cause a computer (e.g., whencompiled and executed) to perform functions described herein. In somecases, the memory 930 may contain, among other things, a BIOS which maycontrol basic hardware or software operation such as the interactionwith peripheral components or devices.

The processor 940 may include an intelligent hardware device (e.g., ageneral-purpose processor, a DSP, a CPU, a microcontroller, an ASIC, anFPGA, a programmable logic device, a discrete gate or transistor logiccomponent, a discrete hardware component, or any combination thereof).In some cases, the processor 940 may be configured to operate a memoryarray using a memory controller. In some other cases, a memorycontroller may be integrated into the processor 940. The processor 940may be configured to execute computer-readable instructions stored in amemory (e.g., the memory 930) to cause the device 905 to perform variousfunctions (e.g., functions or tasks supporting beam dependent DPD). Forexample, the device 905 or a component of the device 905 may include aprocessor 940 and memory 930 coupled to the processor 940, the processor940 and memory 930 configured to perform various functions describedherein.

The communications manager 920 may support wireless communication at awireless device in accordance with examples as disclosed herein. Forexample, the communications manager 920 may be configured as orotherwise support a means for applying a first set of DPD coefficientsto a set of multiple antenna elements to form a first transmit beam. Thecommunications manager 920 may be configured as or otherwise support ameans for determining to switch from using the first transmit beam tousing a second transmit beam that is different from the first transmitbeam. The communications manager 920 may be configured as or otherwisesupport a means for applying a second set of DPD coefficients to the setof multiple antenna elements to form the second transmit beam, where thesecond set of DPD coefficients is different from the first set of DPDcoefficients. The communications manager 920 may be configured as orotherwise support a means for transmitting signaling using the secondtransmit beam based on applying the second set of DPD coefficients.

By including or configuring the communications manager 920 in accordancewith examples as described herein, the device 905 may support techniquesfor improved communication coverage and reduced power consumption, amongother examples.

In some examples, the communications manager 920 may be configured toperform various operations (e.g., receiving, monitoring, transmitting)using or otherwise in cooperation with the transceiver 915, the one ormore antennas 925, or any combination thereof. Although thecommunications manager 920 is illustrated as a separate component, insome examples, one or more functions described with reference to thecommunications manager 920 may be supported by or performed by theprocessor 940, the memory 930, the code 935, or any combination thereof.For example, the code 935 may include instructions executable by theprocessor 940 to cause the device 905 to perform various aspects of beamdependent DPD as described herein, or the processor 940 and the memory930 may be otherwise configured to perform or support such operations.

FIG. 10 shows a flowchart illustrating a method 1000 that supports beamdependent DPD in accordance with aspects of the present disclosure. Theoperations of the method 1000 may be implemented by a transmittingdevice such as a UE 115 or a base station 105 or its components asdescribed herein. For example, the operations of the method 1000 may beperformed by device 505. In some examples, the device 505 may execute aset of instructions to control the functional elements of the device 505to perform the described functions. Additionally or alternatively, thedevice 505 may perform aspects of the described functions usingspecial-purpose hardware.

At 1005, the method may include applying a first set of DPD coefficientsto a set of multiple antenna elements to form a first transmit beam. Theoperations of 1005 may be performed in accordance with examples asdisclosed herein.

At 1010, the method may include determining to switch from using thefirst transmit beam to using a second transmit beam that is differentfrom the first transmit beam. The operations of 1010 may be performed inaccordance with examples as disclosed herein.

At 1015, the method may include applying a second set of DPDcoefficients to the set of multiple antenna elements to form the secondtransmit beam, where the second set of DPD coefficients is differentfrom the first set of DPD coefficients. The operations of 1015 may beperformed in accordance with examples as disclosed herein.

At 1020, the method may include transmitting signaling using the secondtransmit beam based on applying the second set of DPD coefficients. Theoperations of 1020 may be performed in accordance with examples asdisclosed herein.

FIG. 11 shows a flowchart illustrating a method 1100 that supports beamdependent DPD in accordance with aspects of the present disclosure. Theoperations of the method 1100 may be implemented by a transmittingdevice such as a UE 115 or a base station 105 or its components asdescribed herein. For example, the operations of the method 1100 may beperformed by device 505. In some examples, the device 505 may execute aset of instructions to control the functional elements of the device 505to perform the described functions. Additionally or alternatively, thedevice 505 may perform aspects of the described functions usingspecial-purpose hardware.

At 1105, the method may include applying a first set of DPD coefficientsto a set of multiple antenna elements to form a first transmit beam. Theoperations of 1105 may be performed in accordance with examples asdisclosed herein.

At 1110, the method may include determining to switch from using thefirst transmit beam to using a second transmit beam that is differentfrom the first transmit beam. The operations of 1110 may be performed inaccordance with examples as disclosed herein.

At 1115, the method may include selecting, from a set of multiple DPDcoefficient sets, the second set of DPD coefficients corresponding tothe second transmit beam. The operations of 1115 may be performed inaccordance with examples as disclosed herein.

At 1120, the method may include applying a second set of DPDcoefficients to the set of multiple antenna elements to form the secondtransmit beam, where the second set of DPD coefficients is differentfrom the first set of DPD coefficients. The operations of 1120 may beperformed in accordance with examples as disclosed herein.

At 1125, the method may include transmitting signaling using the secondtransmit beam based on applying the second set of DPD coefficients. Theoperations of 1125 may be performed in accordance with examples asdisclosed herein.

FIG. 12 shows a flowchart illustrating a method 1200 that supports beamdependent DPD in accordance with aspects of the present disclosure. Theoperations of the method 1200 may be implemented by a transmittingdevice such as a UE 115 or a base station 105 or its components asdescribed herein. For example, the operations of the method 1200 may beperformed by device 505. In some examples, the device 505 may execute aset of instructions to control the functional elements of the device 505to perform the described functions. Additionally or alternatively, thedevice 505 may perform aspects of the described functions usingspecial-purpose hardware.

At 1205, the method may include determining the set of multiple DPDcoefficient sets based on a calibration process that identifiesnon-linearity characteristics of the set of multiple antenna elementsfor a set of multiple transmit beams including the first transmit beamand the second transmit beam. The operations of 1205 may be performed inaccordance with examples as disclosed herein.

At 1210, the method may include performing a DPD coefficient calibrationfor each of the set of multiple transmit beams based on a dynamiccalibration schedule that occurs while the wireless device is operating.The operations of 1210 may be performed in accordance with examples asdisclosed herein.

At 1215, the method may include applying a first set of DPD coefficientsto a set of multiple antenna elements to form a first transmit beam. Theoperations of 1215 may be performed in accordance with examples asdisclosed herein.

At 1220, the method may include determining to switch from using thefirst transmit beam to using a second transmit beam that is differentfrom the first transmit beam. The operations of 1220 may be performed inaccordance with examples as disclosed herein.

At 1225, the method may include selecting, from a set of multiple DPDcoefficient sets, the second set of DPD coefficients corresponding tothe second transmit beam. The operations of 1225 may be performed inaccordance with examples as disclosed herein.

At 1230, the method may include applying a second set of DPDcoefficients to the set of multiple antenna elements to form the secondtransmit beam, where the second set of DPD coefficients is differentfrom the first set of DPD coefficients. The operations of 1230 may beperformed in accordance with examples as disclosed herein.

At 1235, the method may include transmitting signaling using the secondtransmit beam based on applying the second set of DPD coefficients. Theoperations of 1235 may be performed in accordance with examples asdisclosed herein.

FIG. 13 shows a flowchart illustrating a method 1300 that supports beamdependent DPD in accordance with aspects of the present disclosure. Theoperations of the method 1300 may be implemented by a transmittingdevice such as a UE 115 or a base station 105 or its components asdescribed herein. For example, the operations of the method 1300 may beperformed by device 505. In some examples, the device 505 may execute aset of instructions to control the functional elements of the device 505to perform the described functions. Additionally or alternatively, thedevice 505 may perform aspects of the described functions usingspecial-purpose hardware.

At 1305, the method may include determining the set of multiple DPDcoefficient sets based on a calibration process that identifiesnon-linearity characteristics of the set of multiple antenna elementsfor a set of multiple transmit beams including the first transmit beamand the second transmit beam. The operations of 1305 may be performed inaccordance with examples as disclosed herein.

At 1310, the method may include performing a DPD coefficient calibrationfor each of the set of multiple transmit beams based on powering on thewireless device. The operations of 1310 may be performed in accordancewith examples as disclosed herein.

At 1315, the method may include applying a first set of DPD coefficientsto a set of multiple antenna elements to form a first transmit beam. Theoperations of 1315 may be performed in accordance with examples asdisclosed herein.

At 1320, the method may include determining to switch from using thefirst transmit beam to using a second transmit beam that is differentfrom the first transmit beam. The operations of 1320 may be performed inaccordance with examples as disclosed herein.

At 1325, the method may include selecting, from a set of multiple DPDcoefficient sets, the second set of DPD coefficients corresponding tothe second transmit beam. The operations of 1325 may be performed inaccordance with examples as disclosed herein.

At 1330, the method may include applying a second set of DPDcoefficients to the set of multiple antenna elements to form the secondtransmit beam, where the second set of DPD coefficients is differentfrom the first set of DPD coefficients. The operations of 1330 may beperformed in accordance with examples as disclosed herein.

At 1335, the method may include transmitting signaling using the secondtransmit beam based on applying the second set of DPD coefficients. Theoperations of 1335 may be performed in accordance with examples asdisclosed herein.

The following provides an overview of aspects of the present disclosure:

Aspect 1: A method for wireless communication at a wireless device,comprising: applying a first set of digital pre-distortion coefficientsto a plurality of antenna elements to form a first transmit beam;determining to switch from using the first transmit beam to using asecond transmit beam that is different from the first transmit beam;applying a second set of digital pre-distortion coefficients to theplurality of antenna elements to form the second transmit beam, whereinthe second set of digital pre-distortion coefficients is different fromthe first set of digital pre-distortion coefficients; transmittingsignaling using the second transmit beam based at least in part onapplying the second set of digital pre-distortion coefficients.

Aspect 2: The method of aspect 1, further comprising: selecting, from aplurality of digital pre-distortion coefficient sets, the second set ofdigital pre-distortion coefficients corresponding to the second transmitbeam.

Aspect 3: The method of aspect 2, further comprising: determining theplurality of digital pre-distortion coefficient sets based at least inpart on a calibration process that identifies non-linearitycharacteristics of the plurality of antenna elements for a plurality oftransmit beams including the first transmit beam and the second transmitbeam.

Aspect 4: The method of aspect 3, wherein the calibration processcomprises: performing a digital pre-distortion coefficient calibrationfor each of the plurality of transmit beams based at least in part on adynamic calibration schedule that occurs while the wireless device isoperating.

Aspect 5: The method of any of aspects 3 through 4, wherein thecalibration process comprises: performing a digital pre-distortioncoefficient calibration for each of the plurality of transmit beamsbased at least in part on powering on the wireless device.

Aspect 6: The method of any of aspects 1 through 5, wherein theplurality of antenna elements are grouped into a plurality of radiofrequency modules; and each antenna element of the plurality of antennaelements is associated with a power amplifier.

Aspect 7: The method of aspect 6, wherein the first transmit beam isassociated with a first direction and the second transmit beam isassociated with a second direction that is different from the firstdirection.

Aspect 8: The method of any of aspects 6 through 7, wherein the firstset of digital pre-distortion coefficients and the second set of digitalpre-distortion coefficients are applied by a single digitalpre-distortion engine that is common to the plurality of radio frequencymodules.

Aspect 9: The method of any of aspects 1 through 8, wherein the wirelessdevice is a base station.

Aspect 10: The method of any of aspects 1 through 9, wherein thewireless device is a user equipment.

Aspect 11: An apparatus for wireless communication at a wireless device,comprising a processor; memory coupled with the processor; andinstructions stored in the memory and executable by the processor tocause the apparatus to perform a method of any of aspects 1 through 10.

Aspect 12: An apparatus for wireless communication at a wireless device,comprising at least one means for performing a method of any of aspects1 through 10.

Aspect 13: A non-transitory computer-readable medium storing code forwireless communication at a wireless device, the code comprisinginstructions executable by a processor to perform a method of any ofaspects 1 through 10.

It should be noted that the methods described herein describe possibleimplementations, and that the operations and the steps may be rearrangedor otherwise modified and that other implementations are possible.Further, aspects from two or more of the methods may be combined.

Although aspects of an LTE, LTE-A, LTE-A Pro, or NR system may bedescribed for purposes of example, and LTE, LTE-A, LTE-A Pro, or NRterminology may be used in much of the description, the techniquesdescribed herein are applicable beyond LTE, LTE-A, LTE-A Pro, or NRnetworks. For example, the described techniques may be applicable tovarious other wireless communications systems such as Ultra MobileBroadband (UMB), Institute of Electrical and Electronics Engineers(IEEE) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, Flash-OFDM, aswell as other systems and radio technologies not explicitly mentionedherein.

Information and signals described herein may be represented using any ofa variety of different technologies and techniques. For example, data,instructions, commands, information, signals, bits, symbols, and chipsthat may be referenced throughout the description may be represented byvoltages, currents, electromagnetic waves, magnetic fields or particles,optical fields or particles, or any combination thereof.

The various illustrative blocks and components described in connectionwith the disclosure herein may be implemented or performed with ageneral-purpose processor, a DSP, an ASIC, a CPU, an FPGA or otherprogrammable logic device, discrete gate or transistor logic, discretehardware components, or any combination thereof designed to perform thefunctions described herein. A general-purpose processor may be amicroprocessor, but in the alternative, the processor may be anyprocessor, controller, microcontroller, or state machine. A processormay also be implemented as a combination of computing devices (e.g., acombination of a DSP and a microprocessor, multiple microprocessors, oneor more microprocessors in conjunction with a DSP core, or any othersuch configuration).

The functions described herein may be implemented in hardware, softwareexecuted by a processor, firmware, or any combination thereof. Ifimplemented in software executed by a processor, the functions may bestored on or transmitted over as one or more instructions or code on acomputer-readable medium. Other examples and implementations are withinthe scope of the disclosure and appended claims. For example, due to thenature of software, functions described herein may be implemented usingsoftware executed by a processor, hardware, firmware, hardwiring, orcombinations of any of these. Features implementing functions may alsobe physically located at various positions, including being distributedsuch that portions of functions are implemented at different physicallocations.

Computer-readable media includes both non-transitory computer storagemedia and communication media including any medium that facilitatestransfer of a computer program from one place to another. Anon-transitory storage medium may be any available medium that may beaccessed by a general-purpose or special-purpose computer. By way ofexample, and not limitation, non-transitory computer-readable media mayinclude RAM, ROM, electrically erasable programmable ROM (EEPROM), flashmemory, compact disk (CD) ROM or other optical disk storage, magneticdisk storage or other magnetic storage devices, or any othernon-transitory medium that may be used to carry or store desired programcode means in the form of instructions or data structures and that maybe accessed by a general-purpose or special-purpose computer, or ageneral-purpose or special-purpose processor. Also, any connection isproperly termed a computer-readable medium. For example, if the softwareis transmitted from a website, server, or other remote source using acoaxial cable, fiber optic cable, twisted pair, digital subscriber line(DSL), or wireless technologies such as infrared, radio, and microwave,then the coaxial cable, fiber optic cable, twisted pair, DSL, orwireless technologies such as infrared, radio, and microwave areincluded in the definition of computer-readable medium. Disk and disc,as used herein, include CD, laser disc, optical disc, digital versatiledisc (DVD), floppy disk and Blu-ray disc where disks usually reproducedata magnetically, while discs reproduce data optically with lasers.Combinations of the above are also included within the scope ofcomputer-readable media.

As used herein, including in the claims, “or” as used in a list of items(e.g., a list of items prefaced by a phrase such as “at least one of” or“one or more of”) indicates an inclusive list such that, for example, alist of at least one of A, B, or C means A or B or C or AB or AC or BCor ABC (i.e., A and B and C). Also, as used herein, the phrase “basedon” shall not be construed as a reference to a closed set of conditions.For example, an example step that is described as “based on condition A”may be based on both a condition A and a condition B without departingfrom the scope of the present disclosure. In other words, as usedherein, the phrase “based on” shall be construed in the same manner asthe phrase “based at least in part on.”

The term “determine” or “determining” encompasses a wide variety ofactions and, therefore, “determining” can include calculating,computing, processing, deriving, investigating, looking up (such as vialooking up in a table, a database or another data structure),ascertaining and the like. Also, “determining” can include receiving(such as receiving information), accessing (such as accessing data in amemory) and the like. Also, “determining” can include resolving,selecting, choosing, establishing and other such similar actions.

In the appended figures, similar components or features may have thesame reference label. Further, various components of the same type maybe distinguished by following the reference label by a dash and a secondlabel that distinguishes among the similar components. If just the firstreference label is used in the specification, the description isapplicable to any one of the similar components having the same firstreference label irrespective of the second reference label, or othersubsequent reference label.

The description set forth herein, in connection with the appendeddrawings, describes example configurations and does not represent allthe examples that may be implemented or that are within the scope of theclaims. The term “example” used herein means “serving as an example,instance, or illustration,” and not “preferred” or “advantageous overother examples.” The detailed description includes specific details forthe purpose of providing an understanding of the described techniques.These techniques, however, may be practiced without these specificdetails. In some instances, known structures and devices are shown inblock diagram form in order to avoid obscuring the concepts of thedescribed examples.

The description herein is provided to enable a person having ordinaryskill in the art to make or use the disclosure. Various modifications tothe disclosure will be apparent to a person having ordinary skill in theart, and the generic principles defined herein may be applied to othervariations without departing from the scope of the disclosure. Thus, thedisclosure is not limited to the examples and designs described hereinbut is to be accorded the broadest scope consistent with the principlesand novel features disclosed herein.

What is claimed is:
 1. An apparatus for wireless communication at a wireless device, comprising: a processor; memory coupled with the processor; and instructions stored in the memory and executable by the processor to cause the apparatus to: apply a first set of digital pre-distortion coefficients to a first plurality of antenna elements to form a first transmit beam that is associated with a first loading configuration of the first plurality of antenna elements; determine to switch from using the first transmit beam to using a second transmit beam, the second transmit beam associated with a second loading configuration of a second plurality of antenna elements that is different from the first loading configuration of the first plurality of antenna elements; apply a second set of digital pre-distortion coefficients to the first plurality of antenna elements, the second plurality of antenna elements, or both to form the second transmit beam, wherein the second set of digital pre-distortion coefficients is different from the first set of digital pre-distortion coefficients; and transmit a signal using the second transmit beam based at least in part on applying the second set of digital pre-distortion coefficients.
 2. The apparatus of claim 1, wherein the instructions are further executable by the processor to cause the apparatus to: select, from a plurality of digital pre-distortion coefficient sets, the second set of digital pre-distortion coefficients corresponding to the second transmit beam.
 3. The apparatus of claim 2, wherein the instructions are further executable by the processor to cause the apparatus to: determine the plurality of digital pre-distortion coefficient sets based at least in part on a calibration process that identifies non-linearity characteristics of the first plurality of antenna elements, the second plurality of antenna elements, or both for a plurality of transmit beams including the first transmit beam and the second transmit beam.
 4. The apparatus of claim 3, wherein the instructions are further executable by the processor to cause the apparatus to: perform a digital pre-distortion coefficient calibration for each of the plurality of transmit beams based at least in part on a dynamic calibration schedule that occurs while the wireless device is operating.
 5. The apparatus of claim 3, wherein the instructions are further executable by the processor to cause the apparatus to: perform a digital pre-distortion coefficient calibration for each of the plurality of transmit beams based at least in part on powering on the wireless device.
 6. The apparatus of claim 1, wherein: antenna elements of the first plurality of antenna elements, the second plurality of antenna elements, or both are grouped into a plurality of radio frequency modules; and each antenna element of the first plurality of antenna elements, the second plurality of antenna elements, or both is associated with a power amplifier.
 7. The apparatus of claim 6, wherein the first transmit beam is associated with a first direction and the second transmit beam is associated with a second direction that is different from the first direction.
 8. The apparatus of claim 6, wherein the first set of digital pre-distortion coefficients and the second set of digital pre-distortion coefficients are applied by a single digital pre-distortion engine that is common to the plurality of radio frequency modules.
 9. The apparatus of claim 1, wherein the wireless device is a network entity.
 10. The apparatus of claim 1, wherein the wireless device is a user equipment.
 11. A method for wireless communication at a wireless device, comprising: applying a first set of digital pre-distortion coefficients to a first plurality of antenna elements to form a first transmit beam that is associated with a first loading configuration of the first plurality of antenna elements; determining to switch from using the first transmit beam to using a second transmit beam, the second transmit beam associated with a second loading configuration of a second plurality of antenna elements that is different from the first loading configuration of the first plurality of antenna elements; applying a second set of digital pre-distortion coefficients to the first plurality of antenna elements, the second plurality of antenna elements, or both to form the second transmit beam, wherein the second set of digital pre-distortion coefficients is different from the first set of digital pre-distortion coefficients; and transmitting a signal using the second transmit beam based at least in part on applying the second set of digital pre-distortion coefficients.
 12. The method of claim 11, further comprising: selecting, from a plurality of digital pre-distortion coefficient sets, the second set of digital pre-distortion coefficients corresponding to the second transmit beam.
 13. The method of claim 12, further comprising: determining the plurality of digital pre-distortion coefficient sets based at least in part on a calibration process that identifies non-linearity characteristics of the first plurality of antenna elements, the second plurality of antenna elements, or both for a plurality of transmit beams including the first transmit beam and the second transmit beam.
 14. The method of claim 13, wherein the calibration process comprises: performing a digital pre-distortion coefficient calibration for each of the plurality of transmit beams based at least in part on a dynamic calibration schedule that occurs while the wireless device is operating.
 15. The method of claim 13, wherein the calibration process comprises: performing a digital pre-distortion coefficient calibration for each of the plurality of transmit beams based at least in part on powering on the wireless device.
 16. The method of claim 11, wherein: antenna elements of the first plurality of antenna elements, the second plurality of antenna elements, or both are grouped into a plurality of radio frequency modules; and each antenna element of the first plurality of antenna elements, the second plurality of antenna elements, or both is associated with a power amplifier.
 17. The method of claim 16, wherein the first transmit beam is associated with a first direction and the second transmit beam is associated with a second direction that is different from the first direction.
 18. The method of claim 16, wherein the first set of digital pre-distortion coefficients and the second set of digital pre-distortion coefficients are applied by a single digital pre-distortion engine that is common to the plurality of radio frequency modules.
 19. The method of claim 11, wherein the wireless device is a network entity.
 20. The method of claim 11, wherein the wireless device is a user equipment.
 21. An apparatus for wireless communication at a wireless device, comprising: means for applying a first set of digital pre-distortion coefficients to a first plurality of antenna elements to form a first transmit beam that is associated with a first loading configuration of the first plurality of antenna elements; means for determining to switch from using the first transmit beam to using a second transmit beam, the second transmit beam associated with a second loading configuration of a second plurality of antenna elements that is different from the first loading configuration of the first plurality of antenna elements; means for applying a second set of digital pre-distortion coefficients to the first plurality of antenna elements, the second plurality of antenna elements, or both to form the second transmit beam, wherein the second set of digital pre-distortion coefficients is different from the first set of digital pre-distortion coefficients; and means for transmitting a signal using the second transmit beam based at least in part on applying the second set of digital pre-distortion coefficients.
 22. The apparatus of claim 21, further comprising: means for selecting, from a plurality of digital pre-distortion coefficient sets, the second set of digital pre-distortion coefficients corresponding to the second transmit beam.
 23. The apparatus of claim 22, further comprising: means for determining the plurality of digital pre-distortion coefficient sets based at least in part on a calibration process that identifies non-linearity characteristics of the first plurality of antenna elements, the second plurality of antenna elements, or both for a plurality of transmit beams including the first transmit beam and the second transmit beam.
 24. The apparatus of claim 23, wherein the means for the calibration process comprise: means for performing a digital pre-distortion coefficient calibration for each of the plurality of transmit beams based at least in part on a dynamic calibration schedule that occurs while the wireless device is operating.
 25. The apparatus of claim 23, wherein the means for the calibration process comprise: means for performing a digital pre-distortion coefficient calibration for each of the plurality of transmit beams based at least in part on powering on the wireless device.
 26. The apparatus of claim 21, wherein: antenna elements of the first plurality of antenna elements, the second plurality of antenna elements, or both are grouped into a plurality of radio frequency modules; and each antenna element of the first plurality of antenna elements, the second plurality of antenna elements, or both is associated with a power amplifier.
 27. The apparatus of claim 26, wherein the first transmit beam is associated with a first direction and the second transmit beam is associated with a second direction that is different from the first direction.
 28. The apparatus of claim 26, wherein the first set of digital pre-distortion coefficients and the second set of digital pre-distortion coefficients are applied by a single digital pre-distortion engine that is common to the plurality of radio frequency modules.
 29. A non-transitory computer-readable medium storing code for wireless communication at a wireless device, the code comprising instructions executable by a processor to: apply a first set of digital pre-distortion coefficients to a first plurality of antenna elements to form a first transmit beam that is associated with a first loading configuration of the first plurality of antenna elements; determine to switch from using the first transmit beam to using a second transmit beam, the second transmit beam associated with a second loading configuration of a second plurality of antenna elements that is different from the first loading configuration of the first plurality of antenna elements; apply a second set of digital pre-distortion coefficients to the first plurality of antenna elements, the second plurality of antenna elements, or both to form the second transmit beam, wherein the second set of digital pre-distortion coefficients is different from the first set of digital pre-distortion coefficients; and transmit a signal using the second transmit beam based at least in part on applying the second set of digital pre-distortion coefficients.
 30. The non-transitory computer-readable medium of claim 29, wherein the instructions are further executable by the processor to: select, from a plurality of digital pre-distortion coefficient sets, the second set of digital pre-distortion coefficients corresponding to the second transmit beam. 